Cindy and Axel, The treatment of choice for insulinoma is surgical removal and biopsy of the pancreatic tumors. This stops the symptoms (lethargy, pawing at the mouth, staring into space, seziures, weight loss) and prevents the tumors from spreading. In some ferrets the tumors can come back again many months or years later. In my experience this surgery has a high success rate and low complication rate ( with...experienced ferret surgeon, isoflurane anesthesia, heart monitor, antibiotics). Depending on the ferrets physical condition, ferrets up to 8 yrs of age do well with surgery. The second line of treatment includes medication which increase glucose levels and inhibit insulin release in the pancreas (prednisone and diazoxide). These drugs can have side effects including causing secondary infections, precipitating heart and /or kidney failure. If a ferret has any symptoms of insulinoma and one or 2 fasting (3 hr fast) low blood glucose values I recommend surgery rather then wait and see, because we know the condition will progressively get worse. Good Luck, Dr Weiss 301-299-4142 [Posted in FML issue 1351]